Use a direct include of strings headers in chrome/renderer/.

chrome/renderer/spellchecker/spellcheck.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_RENDERER_SPELLCHECKER_SPELLCHECK_H_
 #define CHROME_RENDERER_SPELLCHECKER_SPELLCHECK_H_
 
 #include <string>
 #include <vector>
 
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/platform_file.h"
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "chrome/renderer/spellchecker/custom_dictionary_engine.h"
 #include "chrome/renderer/spellchecker/spellcheck_language.h"
 #include "content/public/renderer/render_process_observer.h"
 #include "ipc/ipc_platform_file.h"
 #include "third_party/WebKit/public/platform/WebVector.h"
 
 struct SpellCheckResult;
 
 namespace WebKit {
 class WebTextCheckingCompletion;
@@ skipping 127 matching lines @@
   // Remember state for auto spell correct.
   bool auto_spell_correct_turned_on_;
 
   // Remember state for spellchecking.
   bool spellcheck_enabled_;
 
   DISALLOW_COPY_AND_ASSIGN(SpellCheck);
 };
 
 #endif  // CHROME_RENDERER_SPELLCHECKER_SPELLCHECK_H_